In a move that will thrill advertisers but make at least some members of the public queasy, a European outdoor advertising firm is rolling out ads using face detection this week.

The technology, called OptimEyes, will let advertisers know how many people are seeing their ads — and what kinds of people are viewing them. OptimEyes promises to identify the gender and rough age of viewers using face detection. Amscreen, which has a network of more than 6,000 screens in Europe in gas stations and convenience stores, is using the technology to let advertisers see the results of their ad spends.

Such ROI data is common for online ads, but has proved elusive for more traditional forms of advertising, like outdoor and TV. As the video above explains, the technology can let advertisers tailor their ads so they run at certain times of day to reach “men of a certain age.” The company isn’t alone in looking to Minority Report-like face detection as a solution for advertising ROI.